1. Field of the Invention
The present invention relates to seal members for coaxial cable connectors, and particularly to seal members for sealing junctions between coaxial cable connectors and terminals.
2. Technical Background
Coaxial cable connectors such as Type F connectors are used to attach a coaxial cable to another object such as an appliance having a terminal adapted to engage the connector. Such connectors must be attached to a coaxial cable using various cable preparation techniques and installation tools. Cable preparation typically requires removal of a portion of the cable jacket, braid, outer conductor and core to expose the cable center conductor. Another portion of the cable jacket is removed to expose the cable braid and cable preparation is completed by folding of the cable braid structure back against the remaining cable jacket. The cable is then inserted into the connector, after which the connector is secured to the coaxial cable. For outdoor applications the connector is generally sealed to the cable either by the internal workings of the connector or by the use of an external sealant, heat shrinkable tubing, rubber cement, fusing tape or rubberized boot.
In order to help maintain the integrity of the coaxial system, moisture should be prevented from entering the terminal/connector/cable junction. In the past, attempts have been made to provide seals by using a rubber type material in the form of a tight fitting ring with an inner bore and an outer diameter or shape. For various reasons, the foregoing attempts have yielded less than satisfactory results. For example, attempts at encapsulating the connectors with tapes, shrink wrappings and plastic or rubber cements are too prone to installation errors, which can result in exposed seams and/or internal voids where moisture can collect and eventually penetrate to the cable junction. Moreover, shrink wrappings require the use of heat or chemicals which further complicate installation procedures. Cements require time to set up and cure, thus prolonging and complicating installation procedures. The use of sealing components such as externally applied flexible boots and/or grommets can result in internal voids where moisture can collect. In addition, installation of tight fitting seal rings is difficult and therefore many times is avoided. Subsequent removal of tight fitting seal rings after a lengthy period of service can be even more difficult than installation.
Additionally, existing seal rings are limited in use by the length of the terminal port on which they are installed. A specific length seal ring must be matched with and installed on a terminal port of compatible length thereby requiring the technician to: a) recognize various port lengths, and b) have a correct assortment of seal rings on hand.
One example of a known seal ring is illustrated in FIG. 1 (Prior Art). A connector 50 is illustrated, as attached to cable 30, and includes a coupler 60. Terminal 10 comprises external threads 12 for mating with connector 50. Seal ring 70 is illustrated as attached to the terminal 10 and has an internal bore 72 that is smaller in diameter than the threaded section 12 and/or smooth section 14 of terminal 10. Weather sealing between seal ring 70 and terminal 10 is accomplished by a press-fit between seal ring inner bore 72 and terminal smooth section 14 and/or threaded section 12.
However, issues arise with this arrangement in that such seal rings cover substantially most of the threads on the appliance port and require that at least a portion of the corresponding cable connector coupler engage the seal ring while engaging the port threads. This engagement during tightening can cause difficulty in turning the connector coupler, thus making the connector hard to install.